The 2-56 UNC stainless steel hexagon socket head cap screw is a precision fastener designed around a shaft shoulder. It's suitable for assembly applications requiring positioning, limiting, or special mechanical properties. Below is a detailed description of its custom requirements.
1. Basic Parameter Requirements
Thread Specification: 2-56 UNC.
Material: Available in 304/316 stainless steel, with the rust resistance grade specified. Materials such as titanium alloy and alloy steel are also available.
Surface Treatment: Passivation, nickel plating, electropolishing, PTFE coating, etc.
II. Structural Features
Head Design
Hexagon Socket Specifications: 0.05" or Customizable.
Head Diameter: Standard 4.0mm (Adjustable).
Head Height: 2.0mm (Must match the hexagon socket depth).
Shoulder/Rubber Shoulder
Polished Rod Diameter: φ2.5mm ± 0.02mm (Must be larger than the major thread diameter).
Step Height: 1.5mm (Tolerance ±0.05mm required).
Stop Function: Ensures a smooth transition between the step surface and the thread, acting as a mechanical stop.
Thread Length: Customizable based on assembly requirements (e.g., 5mm, 8mm, etc.).
Total Length: To be specified (e.g., 12mm, including head, polished rod, and threaded components).
III. Key Process Requirements
Tolerance Standards: Polished Rod: H7 tolerance.
Thread: Complies with ANSI B1.1 standard, go/no-go gauge inspection.
Concentricity: Deviation between polished rod and thread axis ≤ 0.03mm.
Surface Finish: Polished rod: Ra ≤ 0.8μm (mirror turning or grinding). Threaded: Ra ≤ 1.6μm.
Heat Treatment: Indicate hardness if necessary (e.g., 316 stainless steel solution treated, HRC 22-28).
IV. Testing and Certification
Full Inspection Items: Dimensional tolerance, thread go/no-go, surface defects (cracks/burrs).
Spot Inspection Items: Salt spray test (e.g., 48-hour neutral salt spray), material spectral analysis.
Certification: Provide a material quality test report (MTC) and a mechanical properties test report (e.g., tensile strength ≥ 700MPa).
V. Packaging and Delivery Packaging Method: Blister tray (anti-scratch), vacuum Bag (anti-oxidation), or as per the customer's requirements.
Label identification: Batch number, material, specifications, quantity.
Minimum order quantity: 500-1000 pieces (negotiable for small trial runs).
Lead time: 15-20 days (subject to confirmation of mold/process difficulty).
VI. Notes
Special requirements: If used in high-temperature/corrosive environments, advance notification is required to adjust the material or process.
Drawing confirmation: CAD drawings or schematics with key dimensions are recommended.
Prototype stage: 3-5 samples are provided to verify dimensions and functionality.
The above information can be further refined based on the actual application scenario (e.g., medical equipment, precision instruments). It is recommended to communicate with the supplier details such as load requirements and assembly method (e.g., an interference fit requires adjustment of the polished rod tolerance).
